Linear 公司的LT3518 LED是电流模式DC/DC转换器,内置了用来驱动LED的2.3A, 45V开关。LT3518具有3000:1真色彩PWM调光比,从250kHz 到 2.5MHz的可调工作频率,主要应用在显示器背景光,汽车电子,照明以及扫描仪。本文介绍LT3518的主要性能,方框图以及多种典型的应用电路图。
LT3518 - Full-Featured LED Driver with 2.3A Switch Current The LT®3518 is a current mode DC/DC converter with an internal 2.3A, 45V switch specifically designed to drive LEDs. The LT3518 operates as a LED driver in boost, buck and buck-boost modes. It combines a traditional voltage loop and a unique current loop to operate as a constant-current source or constant-voltage source. Programmable switching frequency allows optimization of the external components for efficiency or component size. The switching frequency of the LT3518 can be synchronized to an external clock signal. The LED current is externally programmable with a 100mV sense resistor. The external PWM input provides 3000:1 LED dimming. The CTRL pin provides further 10:1 dimming ratio.
The LT3518 is available in the tiny footprint QFN UF16 (4mm 4mm) package. The LT3518 provides a complete solution for both constant-voltage and constant-current applications.